UK SWAIS 2C

随着我们的地球变暖，全球平均海平面正在上升。自1900年以来，海平面上升了约20厘米，最初是由于气温升高时水的膨胀和山脉冰川的融化。然而，近年来，格陵兰和南极洲上的大冰盖融化显著增加，陆地冰(冰川和冰盖)的丧失现在是全球平均海平面的最大贡献因素。极地冰盖的海平面相当于几十米，但对温室气体排放增加的反应迟缓(即比全球温度慢)。因此，随着全球变暖程度的加剧，社会正面临着未来几个世纪和几千年海平面上升的长期承诺。这是真的，即使明天全球排放将停止，未来的变暖将保持在2摄氏度以下，这是2015年巴黎协议设定的目标。西南极冰盖(WAIS)相当于4.3米的海平面，是目前观测到的南极洲质量损失最大的部分。这促使一个国际财团成立，从南极洲罗斯海的两个钻探地点回收沉积物，以回答以下问题：WAIS对2摄氏度变暖的敏感度是多少。这项建议展示了英国社区如何通过结合我们在生成综合数据和建模方法方面的独特专业知识来最好地为回答这一关键问题做出贡献并发挥领导作用，以解决三个目标：(1)过去暖期WAIS的配置是什么？(2)WAIS在过去的地质历史中是如何退缩和重新推进的？(3)随着时间的推移，南极地貌的变化如何影响冰动力学？我们将使用先进的实验室方法来确定沉积物的化学指纹，以及这与沉积物来自大陆的哪里、最后一次暴露的时间、沉积距离冰盖边缘有多近以及在什么环境条件下有何关系。通过在数值模型中使用这些信息，我们将克服一个长期存在的限制，即用于预测未来的模型经常提供与过去冰盖配置相反的结果。我们将使用一系列模型，从简单的冰盖模型到高级耦合的冰盖和气候模型，以开发与冰芯和海洋沉积物芯观测一致的过去WAIS与海洋变暖、大气变暖和陆地地形变化有关的动力学和机制的更准确图景。

As our planet is warming, global mean sea level is rising. Since the year 1900 this rise in sea level has been ~ 20 cm, initially due to the expansion of water under warmer temperatures and melting of mountain glaciers. However, over recent years the melting of the large ice sheets on Greenland and Antarctica has increased significantly, and loss of land ice (glaciers and ice sheets) is now the largest contributor to global mean sea level. The polar ice sheets hold many tens of metres of sea level equivalent, but are slow to respond to enhanced greenhouse gas emissions (i.e. slower than global temperatures). With every degree of warming, society is hence facing a long-term commitment in sea level rise for centuries and millennia into the future. This is true, even if global emissions would be halted tomorrow, and future warming would be kept below 2 degrees C, the target set by the Paris agreement in 2015. The West Antarctic Ice Sheet (WAIS) holds 4.3 m of sea level equivalent and is the part of Antarctica where most mass loss is observed today. This motivated the formation of an international consortium to recover sediments from two drill sites in the Ross Sea (Antarctica) to answer the following question: 'What is the sensitivity of the WAIS to 2C warming'. This proposal presents the case how the UK community could best contribute and lead in answering this critical question by combining our unique expertise in generating combined data and modelling approaches to address three objectives: (1) What was the configuration of the WAIS during past warm periods? (2) How did the WAIS retreat and readvance in the geological past? (3) How do changes in the Antarctic landscape through time affect ice dynamics? We will use advanced laboratory methodologies to determine the chemical fingerprint of sediments and how this relates to where on the continent the sediment came from, when it was last exposed, how close to the ice sheet margin it was deposited and under what environmental conditions. By using this information in numerical models, we will overcome a longstanding limitation that the models used to predict the future are often providing contrasting results on past ice sheet configurations. We will use a hierarchy of models, from simple ice sheet models to advanced coupled ice sheet and climate models to develop a more accurate picture of past WAIS dynamics and mechanisms in relation to ocean warming, atmospheric warming, and changing topography on land, consistent with observations from ice cores and marine sediment cores.